1. Field of the Invention
The present invention relates to a determination method for evaluating a friction surface of a vibration type actuator, a vibration type driving apparatus, a vibration type actuator, a vibration type actuator apparatus, a copying machine, and the like.
2. Related Background Art
In conventional vibration type actuators, a vibration member is adapted to form a driving vibration wave in an elastic member by applying alternating signals to a an electro-mechanical energy conversion element (such as a piezoelectric element) of the actuator. A contact member is provided in press contact with a driving surface of the vibration member, and the contact member is frictionally driven relative to the vibration member by the driving vibration wave. A friction member is provided on one of the frictional slide surfaces, for example, on the driving surface of the elastic member. This friction member wears off as a result of friction caused by sliding against the opposing member during driving of the vibration type actuator, and powder resulting from wear sticks to the frictional slide surface, thereby affecting the frictional driving.
An approach for recovering the friction surface is described in Japanese Patent Application Laid-Open No. 61-207186, wherein a member for removing wear particles stuck to the friction surface is provided in direct contact with the friction surface to shave off wear particles adhered thereto.
Japanese Patent Application Laid-Open No. 7-59368 suggests another approach for recovering the friction surface using a friction material containing abrasive grains to remove wear particles stuck to the frictional slide surface.